1. Field of the Invention
This invention relates generally to body treatment care and specifically to counterpressure garments used in emergency treatment of victims suffering from hypovolemic shock and in the presence of intractable bleeding.
2. Description of the Prior Art
Shock is a life threatening condition that results when the body is unable to maintain circulation to the heart, lungs and brain. It may be caused by trauma, blood loss, toxins or other circulatory diminishment. In addition to the routine shock first-aid of lying the victim prone with the lower extremities raised to move blood to the critical organs, it is also known to apply surface counterpressure to the lower extremities sufficient to overcome the pressure in the capillary and venus system to force increased circulation to the critical organs.
Circumferential pneumatic counterpressure (CPC) devices are well known inflatable garments used to apply pressure around the arms, legs and/or abdomen to control intractable bleeding and ameliorate shock. Examples of such devices are described in U.S. Pat. No. 3,933,150 issued Jan. 20, 1976, to Kaplan et al., and U.S. Pat. No. 4,039,039 issued Aug. 2, 1977, to Gottfried. The application of a CPC device causes a dramatic rearrangement of the blood circulation within a victim's body. It causes the victim's blood pressure to rises and the volume of blood available to the heart, lungs and head to greatly increase, while the amount of blood in the extremities is decreased.
The safety of pneumatic CPC devices has been questioned because the garment can be over-pressurized and cause restriction of the respiratory process, acidosis or ischemic injury (where the garment presses the skin against underlying bone). A standard method of pressurizing a CPC is by using an air pump, which in the conditions and excitement surrounding an emergency situation, often result in the ambulance crew over-inflating the garment.
Another problem associated with CPC garments is the rapid pressure drop from the accidental puncturing of one or more bladders. A rapid depressurization could be fatal since the victim's blood pressure can decrease by as much as 60 mm Hg.
Pressurized garments are also susceptible to temperature and atmospheric pressure changes, forcing the ambulance crew to adjust the garment's pressure. For example, if a skier at the top of a mountain is involved in an accident and is placed in a CPC garment, the relative pressure within the garment's bladders will decrease when the skier is brought down to ground level; while outdoor to indoor temperature changes can also raise or lower the relative pressure.
Since the pneumatic pressure fittings are sometimes metallic, a victim might be X-rayed for possible fractures while in the garment. Further, the garment usually cannot be cut away in selected areas to expose portions of the victims body for treatment, as the cutting would open an air bladder and cause depressurization.